Wine glasses that teach cooperation

A pair of wine glasses, which allows the liquid to flow freely between the two glasses. Because liquid finds it's own level, it flows down to the lowest glass. Users must learn to cooperate, to drink their wine.

Clever idea, but I think half the population would have no idea how to actually drink the wine. I don't even know how you'd finish a cup. One person would have to be standing on their head or something.